This invention relates to a telephone system serving premises having a plurality of terminals, such as telephone terminals, offering subscriber selectable features.
A modern private automatic branch exchange (PABX) offers subscribers a choice of many features such as Forward No Answer, Call Forward Busy, Call Forward Always, or Toll Restriction. The features required by each subscriber obviously depend on whether the subscriber is "in" or "out" For example, when a subscriber is "in", he or she may wish to activate the Call Forward No Answer Feature, which forwards the call to a predetermined number, such as a secretary, after a predetermined number of rings, whereas when the subscriber is "out" he or she may wish to forward the call immediately to another number, for example a secretary, a home number or a voice mail box. When the subscriber is out, there is clearly no need for the caller to wait three (or more) rings before the call is forwarded.
Another feature often required by subscribers when they are "out" is Toll Restriction. A subscriber may need to make long distance telephone calls, but to prevent abuse ensure that long distance calls are blocked when that subscriber is not on the premises.
Presently, in order to change the active features the subscriber must remember to reprogram the telephone each time he or she leaves or enters the premises. Often the subscriber will forget to do this, and it can be a major inconvenience if the subscriber is in a rush.
An alternative known method is for the PABX to have a Night Service condition. At a certain time, for example 5:00 p.m. when the receptionist goes home, the PABX is switched over to the night condition and all telephones are put into the night service mode, which may involve different features from those in the day mode. A disadvantage of this system is that many subscribers do not keep regular office hours, and consequently the desired features may not be appropriate at all times. For example, if a subscriber is out during the day a toll restriction feature would not be activated, leaving open the possibility of abuse by say a junior employee.
An object of the present invention is to alleviate the aforementioned disadvantages of the prior art.